John Deere 2955 Hydraulic Issues Help!

[mkt]

I have a 2955 and the issue is after running for some time the brakes don't work, the external hydraulics don't work and steering doesn't work.
It has fluid / oil, all filters including screen has been cleaned and replaced. No oil is getting the pump in front of engine. I removed the 3/4" "supply" line to the small radiator and no fluid is being supplied to the pump when I start the engine.
What could be the problem and what can I check to find out what the problem is?
Thanks all!

 

[Tx Jim]

When sump screen was checked was any debris on screen?? Have you checked to be sure hyd filter relief valve isn't stuck in open position? With 3 pt raised,engine running,look inside hyd filler hole behind seat for moving/spraying oil which would indicate blown rockshaft control valve seals. A shade tree method to check trans pump output is place open clean 5 gallon bucket under hyd filter cover then remove cover,turn engine over for 15 seconds then measure amount of oil in bucket. A high $$$$ hyd flowrater is a better option to check trans pump output. The supply tubes for hyd hi-lo & hyd pto are likely places that can have internal leaks depleting oil supply to frt hyd pump. Have you tested hyd's with hi-lo in both speeds & pto on & off? Does tractor have a frt end loader attached? If so what type valve controls it(ind or scv)
HTH's,Jim

PS: I served as a JD dealer service manager for 13 yrs back in '74-'87. JD closed center hyd problems require good diagnostics to correctly solve the problems.

 

[mkt]

Tx Jim,
Thank you for the reply. Back in January the tractor started acting up. I learned about the screen and I removed the screen and it was full of debris. ( maybe brake pads? not sure). I cleaned the screen and the internal oil filter had collapsed and I replaced it and all other filters.
Yesterday, I put a male nipple in the coupling where the hydraulic "internal" oil filter cover is and started the engine. It pumped oil out of the nipple.
I have not looked to see if the hyd relief valve is open. I can do that later this morning.
Appreciate any help with this issue.
Thanks, Mark

 

[Tx Jim]

You're welcome.
Does tractor have a frt end loader mounted?

 

[mkt]

It did have a loader and I removed it a few months ago. It connected to the Quick disconnects where the oil filter is.

 

[Tx Jim]

The reason I asked if it had a FEL is due to fact the ind.control valve could have a blown inner seal on closed center conversion plug which will cause hyd problems. Experienced that problem yrs back.

 

[mkt]

Appreciate your interest and help. At this time I guess I will see if I see any fluid getting pumped when I remove the oil filler cap behind the seat. Other than that I have no clue. Doesn稚 make sense that no fluid is being supplied to the front pump but I don稚 know how the internals are set up. And I知 no expert or have any experience with JD hydraulics.

 

[mkt]

I went by and checked the hyd fluid level and it was a little low. Added some fluid and started the tractor. Had to rev the engine to get the 3 point hitch to lift. It took a long time but it did raise the disc harrow cylinder. Just barely.
The front hyd pump is making a knocking sound like it is starved for fluid. I'm going to check the filter bypass valve next. Im not sure that the pump isn't going bad.. Hard to say. Thanks

 

[Tx Jim]

One needs to perform good hyd diagnostics before deciding to replace the frt hyd pump.

Many frt pumps have been replaced to determine that the replaced pump was not the problem.

Have you tried raising 3 pt with pto in both on/off position & with hyd hi-lo in both speeds.

I'll also recommend to remove & cap power steering supply line so as to determiner if power steering valve is leaking internally.

Did you check trans pump GPM utilizing 5 gal bucket? Since your tractor has a ported hyd filter cover all one needs to do is remove fitting in filter cover to perform test.

 

[mkt]

I have not checked the trans pump other than with a nipple in the QD and she blew out fluid nicely. But I will tomorrow.
This morning I moved the tractor from the field to home. Dang hyd worked and I could drive it. What that tells me is something is blocking the lines somewhere with debris and over night the debris settles and provides enough flow to front pump. Just a guess. I need someone local to diagnose these problems and provide a fix. I just am not an expert. Tks for all the help!! Really appreciate all your input!!!!

 

[Tx Jim]

If hyd's operated that indicates that frt pump is GOOD but has an oil supply problem when it doesn't operate correctly. Frt hyd pump doesn't have the capability to SUCK oil so therefore oil must be pumped to it by trans pump.

 

[mkt]

I知 going down and try t see what the flow rate is for the rear pump. Also I see a Double headed nut or what may be some type of plug on the top side of the oil filter casting cover.The large hex is 1. 1/4 and the smaller hex is about 3/4 could this be a bypass that you mentioned? Can稚 figure out out how to post pictures from iPhone or I would post a picture. Thanks

 

[Zebrafive]

Does it have HI-Lo trans? I am thinking Hydraulic PTO clutch. Both of these are fed from trans pump. If an internal line breaks, flow will go to sump rather than to front pump.

 

[Kyle_in_Tex]

I知 going down and try t see what the flow rate is for the rear pump. Also I see a Double headed nut or what may be some type of plug on the top side of the oil filter casting cover.The large hex is 1. 1/4 and the smaller hex is about 3/4 could this be a bypass that you mentioned? Can稚 figure out out how to post pictures from iPhone or I would post a picture. Thanks

I wish I had good news for you, but I don't. My friend bought one used, but only test drove it for 20-30 minutes in a lot. He had the same symptoms when he got home. Turns out he had to have the tractor split and replace the pump (and possibly the lines) in the rear. While he was in there, he did a full clutch job, and put all new seals and such. The tractor had 5000 hours on it when he bought it. They had put new tires on it. It probably was used for pulling logs around.

There is some good news, after getting it done, it has been a great tractor for 10 years, other than the normal wear and tear issues. He still loves it.

 

[mkt]

I just did the test and it pumped 4.5 gallons in 1 minute. Cold start about 1/3 throttle. Now what痴 next? Thanks

 

[Kyle_in_Tex]

I just did the test and it pumped 4.5 gallons in 1 minute. Cold start about 1/3 throttle. Now whatç—´ next? Thanks

When the oil heats up after a while, it gets thin and doesn't pump so well. You lose hydraulic pressure across the board.

 

[mkt]

The tractor does not have hi-lo. It has high and low range gear shift. Tractor shows 1455 hours. Thanks everyone!

 

[Kyle_in_Tex]

 

[Tx Jim]

Hyd filter relief valve that I recommended checking is keys 28-31 in photo below.

 

[Kyle_in_Tex]

The tractor does not have hi-lo. It has high and low range gear shift. Tractor shows 1455 hours. Thanks everyone!

It could be that you possibly have hydraulic oil going through a small orifice, such as a barely open valve or something, that is heating the oil up. Check all your control valves and joystick valves for easy and free operation. Anything that should be self centering, should be centered. Anything that should be shut, is shut. So on and so forth. Cable operated valves are very often a culprit. I have to lube stuff with spray lubes, and sometimes take them apart to free up corrosion.